Isolation and analysis of xlnR, encoding a transcriptional activator co-ordinating xylanolytic expression in Aspergillus niger.
Complementation by transformation of an Aspergillus niger mutant lacking xylanolytic activity led to the isolation of the xlnR gene. The xlnR gene encodes a polypeptide of 875 amino acids capable of forming a zinc binuclear cluster domain with similarity to the zinc clusters of the GAL4 superfamily of transcription factors. The XlnR-binding site 5'-GGCTAAA-3' was deduced after electrophoretic mobility shift assays, DNase I footprinting and comparison of various xylanolytic promoters. The importance of the second G within the presumed XlnR binding site 5'-GGCTAAA-3' was confirmed in vitro and in vivo. The 5'-GGCTAAA-3' consensus sequence is found within several xylanolytic promoters of various Aspergillus species and Penicillium chrysogenum. Therefore, this sequence may be an important and conserved cis-acting element in induction of xylanolytic genes in filamentous fungi. Our results indicate that XlnR is a transcriptional activator of the xylanolytic system in A. niger.
van Peij
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NN
Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, The Netherlands.
Visser
J
J
de Graaff
L H
LH
D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001667:Binding, Competitive; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D018983:DNA Footprinting; D004271:DNA, Fungal / Q000737:chemistry; D003850:Deoxyribonuclease I; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic; D014170:Transformation, Genetic; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000378:metabolism*; D014995:Xylosidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016335:Zinc Fingers / Q000235:genetics / Q000502:physiology
D004271:DNA, Fungal; D005656:Fungal Proteins; D015534:Trans-Activators; C115443:XlnR protein, Aspergillus; D014990:Xylans; D003850:Deoxyribonuclease I; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase